aria2是一款文件下載工具。它支持的協議：HTTP(S)，FTP，BitTorrent(DHT,PEX,MSE/PE)和Metalink。它擁有強大的分段下載能力，通過多個源地址和多種協議的方式來下載文件，並且將你的下載帶寬達到最大化。它甚至支持從同時從HTTP(S)/FTP 和 BitTorrent 下載文件，當從HTTP(S)/FTP下載的數據被上傳到the BitTorrent swarm，使用 Metalink的大量校驗和，當下載類似BitTorrent的文件時aria2自動的校驗大量的數據。
它一直被Tatsuhiro Tsujikawa積極的開發着。歡迎提出新的功能需求和內容。請通過網站頁面底部的聯繫信息進行聯繫。
原文：
aria2 is a utility for downloading files. The supported protocols are HTTP(S), FTP, BitTorrent (DHT, PEX, MSE/PE), and Metalink. It has a powerful segmented downloading ability, downloading a file from multiple sources and multiple protocols and utilizing your download bandwidth to the maximum. It even supports downloading a file from HTTP(S)/FTP and BitTorrent at the same time, while the data downloaded from HTTP(S)/FTP is uploaded to the BitTorrent swarm. Using Metalink's chunk checksums, aria2 automatically validates chunks of data while downloading a file like BitTorrent.
It is being actively developed by Tatsuhiro Tsujikawa. Feature requests and comments are all welcome. Please refer to the contact information at the bottom of this page.